Tropical lizard species adapts to cooler clime

Washington, Nov 27 (IANS) A tropical lizard species native to Puerto Rico has adapted to the cooler winters of Miami, suggesting its ability to survive climate change.

"We are not saying that climate change is not a problem for lizards. It is a major problem. However, these findings indicate that the thermal physiology of tropical lizards is more easily altered than previously proposed," said Duke University biologist Manuel Leal, the co−author of the study.

Scientists previously proposed that because lizards were cold−blooded, they wouldn't be able to tolerate or adapt to cooler temperatures, the journal The American Naturalist reports.

Leal and his graduate student Alex Gunderson captured anolis cristatellus from Miami's Pinecrest area and also from northeastern Puerto Rico. They brought the animals back to their North Carolina lab, slid a thermometer in each lizard's cloaca and chilled the air to a series of cooler temperatures, according to a Duke statement.

The scientists then watched how easy it was for the lizards to right themselves after they had been flipped on their backs. These lizards flipped themselves over in temperatures that were three degrees Celsius cooler than the lizards from Puerto Rico.

Animals that flip over at lower temperatures have higher tolerances for cold temperatures, which is likely advantageous when air temperatures drop, Leal said.

Leal explained that a difference of three degrees Celsius is "relatively large and when we take into account that it has occurred in approximately 35 generations, it is even more impressive".

Most evolutionary change happens on the time scale of a few hundred, thousands or millions of years. Thirty−five years is a time scale that happens during a human lifetime, so we can witness this evolutionary change, he said.